


Call Me Onii-chan!

by Arlerted



Series: Oh, I Assure You, We’re Brothers! [2]
Category: Ao no Exorcist | Blue Exorcist
Genre: Boys talk, Gen, Rin and Yukio being brothers, Shima wants to be a big brother, Sibling Bonding
Language: English
Status: Completed
Published: 2017-03-06
Updated: 2017-03-06
Packaged: 2018-09-28 17:01:14
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,461
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10140551
Author URL: https://archiveofourown.org/users/Arlerted/pseuds/Arlerted
Summary: Omake from Fraternal Twins are Still Twins!Shima was left alone in Okumura's dorm after falling asleep during their 'homework marathon session'. He found out that it's fun to tease both of these twins and claimed the big brother title.





	

**Author's Note:**

> This is an omake that gets so long that it deserves to have its own one-shot. You can read the original story in the series (or you can go to this link > http://archiveofourown.org/works/9945368)
> 
> Enjoy!

“Shima-kun… Shima-kun, wake up.” Yukio shook the shoulder of his pink haired student. Shima was drooling all over what seems like a homework he gave them last week.   


“Huh? What?” Shima jerked up from the sudden touch, wiping the edge of his mouth with his sleeve. “ _Wa-wakasensei…_ Where is…” He looked around, it’s getting dark outside. “Bon…”   


“It seems that they left you here…” Yukio sighed and sat on the adjacent side of Shima. He placed a tray with a bowl of rice, a big piece of hamburger steak, then two small bowl with soup and meat stew in it.   


_Right. He will be back by dinner, that was what Okumura-kun said._ Shima started to collect his messy stuff. “Sorry, I’ll go back to my own dorm now…” But his stomach betrayed him by letting out a loud growl. He groaned, remembering that they skipped lunch to marathon on those homework.   


“You can stay and eat here if you want.” Yukio smiled, “Since you’re here at dinner time there’s an extra serving over there, must be yours.” He pointed at a counter on the far end of the large room.   


Shima nodded, face turns red because of the embarrassing situation. He picked up one of the tray and bring it to the table, squinting his eyes when he saw Yukio’s.   


“What do you get?” Yukio seemed to notice how Shima stared at his tray.   


“Rice, shrimp and vegetable tempura, soup, and a veggie-mushroom-chicken stir-fry. Why is it difference from yours, sensei?”  


“Sir Pheles assigned a… _cook_ … for this dorm and as you know there are several dorms in the True Cross Academy. Since this place is empty we got leftover ingredients from other dorms or school’s cafeteria. It resulted in random variety of dish. Not that I complained. It’s nice to have different meals each time since they all are delicious and balanced. Sometimes it ended in a quarrel because my brother wants something of mine and took it.” Yukio sighed after the long explanation. He opened the plastic cling wrap that covers his tray. “By the way, have you seen my brother?”

“Okumura-kun said he’s going out this after—”

“I’m home!” Shima was cut off by a voice that is unmistakably Rin’s coming from the hallway, followed by Kuro’s meow.

“Speak of the de- son of Satan.” He snickered at his own joke.

Rin entered the dining room and startled when he saw Shima. “What are you doing here?”

“I… fell asleep and they left me.”

“Haha! That’s stupid!” Rin laughed, Kuro following him behind. “It’s alright, the more the merrier, right Kuro?” Rin places a bowl on the far end of the table and poured Kuro’s food.

 ** _Yes, Rin! Itadakimasu!_** Kuro ate almost immediately, tails swinging left and right in joy.

“I’m staaaaaarving.” Rin walked to get his own tray when Yukio said, “Don’t forget to wash your hand, Nii-san.”

“Shut up, I’m not a child and you’re not my mother!” Rin sneered, but washing his hand anyway. When he got back to the table, Shima and Yukio already started to eat. He took a chair beside Yukio, but instead of eating he stared at Yukio’s plate.

Yukio glanced at his brother’s plate. Rice, grilled mackerel, miso soup, and green pepper stir-fry, the plainest meal of them all. “What, Nii-san?”

“Yukio you’ve got meat!” Rin pointing at the hamburger steak _and_ meat stew. 

“Yes, yes.” Without any further ado, he pushed his tray to his brother and received the other one.

“You’re the best, Yukio! Itadakimasu!” Rin started eating with a big smile, he loved meat.

“Hey, hey, you can’t just take his food like that, Okumura-kun!” Shima shook his head pretending to look disappointed at Rin’s action.

“Oh, you don’t know.” Rin tried to speak with his mouth full, “This guy really loves fish, you know! When we’re kids I told him once that if he eat fish for meals every single day he will start to grow scales and fins. Guess what, he actually believes it, crying and saying that he will never eat fish again.” 

“Nii-san, stop blabbering and don’t speak with your mouth full of food like that, you will choke and I will not help you.” Yukio kept his usual straight face, even though he is embarrassed by that story. He need to keep his cool in front of students! 

“Here, sensei, I’ll give you one of my tempura!” Shima pick one of the breaded shrimp with chop stick and placed it on Yukio’s dish plate.

“Oh, thank you.” Yukio does not reject the offer and smiled at Shima. He is ignoring Rin’s complain that it’s not fair that he didn't get anything.

“Alright, alright, you can have this, Okumura-kun.” Shima placed one of the vegetable tempura to Rin’s plate with a smirk.

“That’s not fair!” Rin complained but eat it anyway. He then cut his hamburger steak in half, looking conflicted for a moment. Rin pick the bigger size and moved it to Yukio’s plate. “There! You’d better eat a lot since you’re working all day, four eyes!”

Yukio only mutters a ‘Yes… Yes…’ but Shima noticed a thin smile on his face. “Aw, are you trying to act like a big brother?”

“Shut it and eat, Shima!”

“Hey, _Wakasensei_ , when is your and Okumura-kun’s birthday?” Satisfied that he managed to tease Rin once again, Shima turned to Yukio. 

“December 27th.” Yukio answered, “Why?”

“Oh! Mine is July 4th! That means I am older than both of you, maybe you guys should call me Onii-san.” 

“Like hell I will!” Rin managed to bark at Shima between swallowing and chewing.

“And why is that, Nii-san?” Yukio ate his food slowly, complete opposite of his brother. 

“Well, for starters, Shima is too irresponsible!”

“Uh-huh.” Yukio nodded, lifting a finger to count.

“He is always slacking around!”

“Hmm, hmm.”

“His grade isn’t that great either!”

“Speak for yourself.”

“Hey, hey, don’t you have anything good about me in your head?” Shima complained with a fake frown.

“Shima is a pervert too! Well I guess it can be a positive side since we can trade some _stuff._ Yukio is such a hardass, I bet he never even touched an ero-magazine[1] before!” 

“We are raised in a church, Nii-san!” A faint but noticeable shade of red appears on Yukio’s cheeks. 

“Oh please, old man once give me an ero-magazine to shut me up because I found it in his bag!”

Yukio recalled the one time when Shura stuffed his suitcase with bunch of SM Magazine. It was back when he’s on his Exwire exam trip. But he destroyed any evidence of that event and will definitely carry that story to his grave. He assumed the same thing also happened to his father.

“What?! Satan gave you an ero-magazine? I bet it’s HOT!” Shima looked at Rin with disbelieved in his eyes, not even conscious of that horrible pun.

“Satan?! No! Do you want to get punched in the face? My old man was and will always be Fujimoto Shiro!”

Shima is silent with a dumbfounded expression on his face. “Reverend Fujimoto THE previous Paladin is your father? _And_ he gave you an ero-magazine? That’s even more shocking!” 

“Look at Shima, Yukio. He was raised in a temple, his whole family is monk!” 

“But Sensei, you seriously never have one before? Do you want me to bring some of mine here next time?” Shima is suddenly standing up, staring at Yukio with a thumb up. “I mean what kind of 15 years old boy never touched an ero-magazine before?!” 

“The one that currently have a job as _your_ teacher at the Exorcist cram school, Shima-kun. Do you want me to give you an F?” Yukio’s face darkened. 

“Hey that is a power abuse!”

“Let’s see. My brother is irresponsible,” Yukio started to talk. He is trying to leave the topic of ero-magazine behind. “I can’t even left him alone for a second without worrying about another death sentence. He never listen to orders and always acted on his own.” Yukio threw a glare at Rin.   


“My brother is also a slacker. I take some time out of my schedule to sit down and help with the cram school homework he still managed to fail somehow.” Another sharp glare. Rin looked away, puckering his lips.   


“Last one, grade huh? Shima-kun scored a 75 in my class last time, while you scored 60, Nii-san.” He took a deep breath, “So, Shima-kun, when will you move in to become my new brother?” He looked up to Shima, putting on innocent face “Would you like me to call you Nii-san, Aniki, or…?”   


Shima is amused seeing _the other_ _side_ of Okumura-sensei that loves to tease his brother as well. “Perhaps you can start with Onii-chan and I’ll call you ‘Yuki-chan’ like Shiemi-san did.”   


“No, Yukio, I’m sorry, I’ll do my test better next time, don’t left me for this pink haired pervert! You never even call me ‘Onii-chan’, I will not permit that!”   


“Alright, I’ll call you Oni from now on.” [1]  


“What did you say?!”

“Haha, I’d love to have two cute little brother like you…” Shima is already finished with his meal. He placed his chopstick and propped his chin on both of his palm. These brothers are adorable, puppies kind of adorable. This triggered another wave of Rin rambling about ‘no way in hell’.   


Yukio sighed at the two’s further arguments, it’s not bad having a company sometimes, he thought to himself. He should try to invite the cram school students to eat here or have tea more often. He could use ‘helping them with homework’ as a bait, as long as he’s not too busy.

“Doesn’t you guys get lonely in here? Just the two of you in this huge and empty dorm?”   


Shima’s question snapped him from his thought. “Hmm, I’m always occupied with work, reports, or cram school stuff.” Yukio never think about this before.

“Yeah, he is. I made him signed a deal that state we must eat dinner together every night, no matter what. If not, you need to pay 500 yen per hour of lateness!” Rin said grumpily, drinking broth that remains from his soup and placed his chopstick.  


“That is just your way to get more pocket money out of mine…” Yukio fixed his glasses, then looked at Shima, “Want me to have a quick look at those homework?”  


Shima nodded and hands his papers. “Don’t be like that, Sensei. I’m sure that even the son of Satan gets lonely if he’s being left alone in here every night…”  


Really? Yukio never considered that. After all, Rin is always either cheerful or complaining, full of energy, not… lonely. Thinking back, he never spend much time with his brother beside breakfast. Sometime they spent lunch time together (to keep his _fangirls_ away). They meet at the cram school, as teacher and student, then at dinner. Usually after dinner he went straight to reports and class materials. He never really listened to his brother’s complains as well. He think it was… stupid... for brother to complain about all those reports or homework. His workload is at least three times in quantity and difficulty. Then again he always judged it through his standard. He is Okumura Yukio who started exorcist training at seven and climb up to Middle First Class at the young age of 15. Compared to his brother who… only find out about a whole new world of exorcists and demons less than a year ago. He is a jerk, just like Rin said.   


“Nii-san I’m sor—” He looked up to Rin who’s already standing up. Rin placed his hand on Yukio’s head and ruffled his hair, “Worry about your job, little brother, don’t worry about me, cause I don’t know how I supposed to survive with two thousand yen a month if not for your salaries!". "Besides Kuro is here. That damned clown always invited himself every now and then…”. Rin gave Yukio his usual _sunshine_ smile, the smile that he always use to cheer Yukio up. “Check on mine too while you’re at it!” he ran back to their room to fetch his paper.   


Yukio took of his glasses and place it on the table, trying to fix his hair. He complained about how his brother haven’t even wash his hand under his breath.   


“Sensei, you do look like Okumura-kun especially with that messy hair if you don’t wear your glasses.”   


“Of course, he is my brother, after all.” Yukio only smiled and put on his glasses back.  


Shima thought he saw Yukio’s glasses glinted.   


“Let’s begin. You need to check number 5, 9, and 10. You can find answer for number 15 to 20 on the book which I told you to read at our third meeting. Ff you already forgot, it’s about the properties of--”  


“Wait, wait, let me jot this down!” Shima did not expect such a long and fast response. He scrambled to find his pen and paper while Yukio keeps on talking.   


“Hey! Don’t get started without me!” Rin shouted from the hallway.

Kuro yawned, looking at Yukio repeatedly smacking Rin’s head with a scroll of paper. "Not even five minutes and you already mess this up, Nii-san?"

Shima desperately flipped through his book trying to find the page Yukio talks about. “You seally considered Aria as your next meister. You’re chanting the material of this class faster than Bon chanting fatal verses for god’s sake!”

“Shima-kun, do you want to get smacked in the head as well? I’m not supposed to do any physical harm to the student, but we’re not in a classroom right now.”

With that Shima shut his mouth and focused on marking his book with a highlighter.   
  


“How come you always hit me then?!”

“Next one is about wounds inflicted by fire-type demons, open page 83.” Yukio fixed his glasses again.

“Huh? We are on page 83.” Shima searched the page for the word ‘fire’.

“Of that book.” Yukio pointed at another volume of their reference book.

“OI!” Rin and Shima’s synchronic protest echoed throughout the empty building.

These three keep that up till Yukio realizes it’s already past 10 o’clock. Shima found 17 missed call from Bon, that's his clue for saying goodbye. After that Rin collects the dishes to wash it while Yukio went out to Mephisto’s office using one of his keys. He needs to deliver some reports, asking Rin to not wait for him.

 ** _Rin, it’s nice having other people around, right?_** Kuro who sat on the counter waiting for Rin yawned again.   
  


“Yeah, that’s why I told Shima to invite everyone too tomorrow!” Rin grinned, drying his hand and picking up Kuro, “Let’s go to bed!”

**Author's Note:**

> [1] Oni means demon 
> 
> Thanks for reading! I hope you like it. 
> 
> Comments, critiques, or prompts for upcoming oneshots about Okumura Twins are welcomed.   
> If you found any mistake please kindly point it out and I'll fix it faster than lighting.


End file.
